fbdev: msm: Avoid runtime sus/res for DP/HDMI

A race condition is seen between DP pan_display commit
path and pm runtime suspend when DP cable is inserted
when device is in suspend. This causes commit failure
and subseqently display won't wake up from suspend.
Avoid runtime suspend/resume of DP lower interface to
resolve this.

Change-Id: Ia1aea19799df718e0713d0cf0ccc3237bb7a31f3
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>